fix(google): disable pinned dns for image generation (#59873)

* fix(google): restore proxy-safe image generation (#59873)

* fix(ssrf): preserve transport policy without pinned dns

* fix(ssrf): use undici fetch for dispatcher requests

* fix(ssrf): type dispatcher fetch path

---------

Co-authored-by: Vincent Koc <vincentkoc@ieee.org>

extensions/tlon/src/urbit/auth.ssrf.test.ts

@@ -37,6 +37,7 @@ describe("tlon urbit auth ssrf", () => {
     const cookie = await authenticate("http://127.0.0.1:8080", "code", {
       ssrfPolicy: { allowPrivateNetwork: true },
       lookupFn,
+      fetchImpl: mockFetch as typeof fetch,
     });
     expect(cookie).toContain("urbauth-~zod=123");
     expect(mockFetch).toHaveBeenCalled();